Marking device for a mould

ABSTRACT

The invention discloses a marking device comprising: a head ( 8 ) to flush with the internal surface of a mold ( 6 ), the side ( 14 ) of the head facing inside the mold having a mark and means ( 16 ) for driving the head in rotation; a threaded cylindrical body ( 10 ) forming a single piece with the head ( 8 ) of the device; optionally a threaded socket ( 2 ) with an external diameter corresponding to the external diameter of the head ( 8 ) of the device and its internal screw thread corresponding to the threading of its body, such that when the body is screwed in the socket, the resulting assembly has a cylindrical circular shape.

[0001] The subject of the present invention is a marking device for amould, for injection or press moulding of parts made of syntheticsubstances or pressure die-cast parts.

[0002] This invention relates to the moulding of parts which need to beidentified, particularly by a date of manufacture. To do this, a deviceis positioned in the mould.

[0003] There are in existence inserts which comprise a number of parts,which can move with respect to each other. By altering the relativeposition of two parts, it is possible to alter the marking to be made onthe part. Thus, for example, a first part on which there is engraved anarrow and the indication of a year can rotate in an annular part bearingthe numbers 1 to 12. By rotating the part placed on the inside, thearrow can point to one of the numbers engraved on the outer part. Thismakes it possible to indicate the month of manufacture on parts made ina mould fitted with such a marking device.

[0004] To reduce the cost of a mould, there are also marking deviceswhich consist of just one part positioned in the mould. This part is,for example, a cylindrical part placed in a housing of a complementaryshape. This part, generally of circular cross section, is fitted tightlyin its housing, in order to prevent any relative movement between themarking device and the wall of the mould.

[0005] However, these marking devices bear an indication that themanufacturer may need to modify. This may, for example, be theindication of a year, or a symbol liable to change (product mark,customer reference, etc.).

[0006] The drawback of these marking devices is that it is difficult tochange them. They are not easy to remove and this removal generallyleads to damage preventing the marking device from being reused, or evendestroying it. Indeed it is not uncommon for it to be necessary to makea hole in the marking device in order to be able to extract it from itshousing.

[0007] This takes a great deal of time. Furthermore, when a hole isdrilled, chips are produced and these run the risk of falling into themould. Finally, there is the risk of damaging the mould.

[0008] The object of the invention is therefore to provide a simplemarking device intended to have a fixed position in a mould, but whichcan be readily removed and refitted.

[0009] To this end, it proposes a marking device which comprises:

[0010] a head intended to lie flush with the internal face of the wallof the mould, that face of the head that faces towards the inside of themould having a marking and means allowing the head to be turned,

[0011] a threaded cylindrical body forming a single piece with the headof the device.

[0012] This marking device can be screwed directly into the interiorwall of the mould, such that the head lies flush with this wall. Thewall of the mould then has a tapped hole, the shape of which correspondsto the shape of the device. To change the marking made on the partsmanufactured in the mould, all that is required is for the markingdevice to be unscrewed and another marking device of the same shape butwith the desired marking to be screwed back in in its place.

[0013] If the wall of the mould already has a housing for housing amarking device, it is possible to insert into this housing a part whichmatches the shape thereof, and to make in this intermediate part atapped hole to allow the marking device according to the invention to behoused.

[0014] Advantageously, the marking device has a head of circularcylindrical shape, with an outside diameter that is greater than theoutside diameter of the body. It is then possible to achieve a tight fitbetween the head of the marking device and the wall of the mould, at theperipheral surface of the head.

[0015] In this last instance, a part of frustoconical shape preferablyconnects the head of the device to its body, so as to obtain a betterfit of the device in its housing.

[0016] In instances where the wall of the mould does not have a tappedhole, but only has a housing of circular cylindrical shape, the markingdevice further comprises a tapped bush, the outside diameter of whichcorresponds to the outside diameter of the head of the device, and thetapping of which corresponds to the screw thread of its body, so thatwhen the body is screwed into the bush, the entity thus formed is ofcircular cylindrical shape. This assembly can then sit in the wall ofthe mould. Of course, the outside diameter of the bush and of the headwill be adapted to suit the inside diameter of the housing in the wallof the mould.

[0017] For the marking devices according to the invention and describedhereinabove, the means for turning the head are advantageously astraight slot passing through the centre of that face that faces towardsthe inside of the mould. However, it may be any other means such as, forexample, a hexagonal cylindrical recess or a square shape in relief.

[0018] In any case, the invention will be clearly understood from thedescription which follows, with reference to the appended diagrammaticdrawing which depicts, by way of non-limiting examples, two embodimentsof a marking device according to the invention.

[0019]FIG. 1 is a view in exploded perspective of a first marking deviceand of part of the mould housing this device,

[0020]FIG. 2 is a view in longitudinal section of this first device and

[0021]FIG. 3 is a view in section, corresponding to

[0022]FIG. 2, of a second marking device.

[0023] A marking device consisting of two parts, a bush 2 and an insert4, is depicted in section in its position in which it is fitted in awall of a mould 6, in FIG. 2.

[0024] The insert 4 has a head 8 and a body 10 connected by a connectingregion 12.

[0025] The head 8 is of circular cylindrical shape. It has a face 14intended to lie flush with the internal face of the wall of the mould 6.This face has an indication, which may be recessed or in relief. Assuggested by FIG. 1, this indication may correspond to the year ofmanufacture of the parts manufactured in the mould. It may of course beany other indication. This face 14 also has a slot 16 extending rightacross a diameter of the face 14. This slot 16 is intended to take theend of a screwdriver (not depicted).

[0026] The body 10 is also of circular cylindrical shape. The body 10and the head 8 are coaxial. The body 10 is threaded over its entirelength. Its outside diameter is smaller than the outside diameter of thehead 8 of the insert.

[0027] The connecting region 12 is frustoconical. It connects, wideningas it does so, the body 10 to the head 8 of the insert.

[0028] The bush 2 is of circular cylindrical shape. It has a tapped hole18. The tapping of this hole corresponds to the screw thread of the body10 of the insert. The outside diameter of the bush 2 is essentiallyequal to the outside diameter of the head 8 of the insert. At the sameend as the open end of the tapped hole 18, the bush has a conicalsurface 20 extending from the outside free edge of the bush inwards.This conical surface corresponds to the cone angle of the connectingregion 12 of the insert.

[0029] Thus, when the insert body is screwed into the tapped hole, theconnecting region 12 comes to rest against the conical surface 20. Theassembly formed by the insert 4 and the bush 2 is of circularcylindrical shape. The peripheral surface of the head 8 of the insertextends the peripheral surface of the bush 2 (FIG. 2).

[0030] This assembly formed by the bush 2 and the insert 4 is intendedto lie in a circular cylindrical housing 22 formed in the wall of themould 6. This assembly is tightly fitted into the housing 22. The tightfit allows the bush 2 and the insert 4 to be held in place. However, itis possible to unscrew the insert 4 from the bush 2. The height of thehead 8 is relatively small, which means that the tight clamping exertedon the head 8 does not prevent the insert from being unscrewed.

[0031] Thus it is easy to change the marking on the parts manufacturedin the mould 6. All that is required is for the insert 4 in place in thebush 2 to be unscrewed so that it can be replaced by another insert, ofidentical shape but exhibiting different markings.

[0032]FIG. 3 depicts an alternative form. In this alternative, there isthe same insert 4 as there was in the embodiment described above, butthe bush 2 has disappeared.

[0033] The housing made in the wall of the mould is different. It is nolonger a circular cylindrical hole, but a stepped hole, part of which istapped.

[0034] Starting from the inner part of the mould, the housing has acircular cylindrical part, the height and diameter of which correspondto the height and diameter of the head 8 of the insert. The housing thennarrows and has a frustoconical surface corresponding to the connectingregion 12. Finally, the blind end of the housing is tapped and thetapping corresponds to the screw thread on the body 10 of the insert.

[0035] When the insert 4 is fitted into the housing, its head 8 liesflush with the internal face of the wall of the mould. As was the casewhen the insert was mounted in a bush, the conical connecting surfaceallows the insert to position itself correctly and be a good fit.

[0036] As goes without saying, the invention is not restricted to theembodiments described hereinabove by way of non-limiting examples; onthe contrary, it encompasses all alternative forms thereof.

1. Marking device for a mould, comprising: a circular head (8) intendedto sit in a housing (22) formed in a wall of the mould and of a diameteressentially equal to the diameter of the head (8) and to lie flush withthe internal face of the wall of the mould (6), that face (14) of thehead that faces towards the inside of the mould having means (16)allowing the head to be turned, and a threaded cylindrical body (10)forming a single piece with the head (8) of the device, characterized inthat that face (14) of the head that faces towards the inside of themould has a marking distinct from the means (16) of turning.
 2. Markingdevice according to claim 1, characterized in that the head (8) is ofcircular cylindrical shape, with an outside diameter that is greaterthan the outside diameter of the body (10).
 3. Marking arrangementaccording to claim 2, characterized in that a part (12) of frustoconicalshape connects the head (8) of the device to its body (10).
 4. Markingdevice according to either of claims 2 and 3, characterized in that itfurther comprises a tapped bush (2), the outside diameter of whichcorresponds to the outside diameter of the head (8) of the device, andthe tapping of which corresponds to the screw thread of its body, sothat when the body is screwed into the bush, the entity thus formed isof circular cylindrical shape.
 5. Marking device according to one ofclaims 1 to 4, characterized in that the means for turning the head (8)are a straight slot (16) passing through the centre of that face (14)that faces towards the inside of the mould.